1. Field of the Invention
The present invention relates to a watertight connector provided with an inertial locking mechanism.
2. Description of the Related Art
When a pair of connector housings of a watertight connector are connected with each other, an operator might mistakenly judge that the connection is completed when connection resistance of the entire connector increases. The increase of a connection resistance could be caused by a waterproof ring provided between the two connector housings, a connection resistance acting between terminals, and the like even though the connector housings are still being connected. An inertial locking mechanism is used in the prior art to prevent the connector housings from being left partly connected. The inertial locking mechanism includes a connection resistance generating means for temporarily generating a connection resistance larger than the connection resistances by the waterproof ring and by the terminal fittings during the connecting operation. The operation can feel a sudden decrease in connection resistance when the connecting operation overcomes the connection resistance generated by the connection resistance generating means and passes a connection resistance generating area. The two connector housings then can be connected properly by a force exerted to pass the generating area, i.e. an inertial force.
A prior art watertight connector provided with such an inertial locking mechanism was developed by the applicant of the present application, and is shown in FIG. 9. The prior art connector includes a pair of resistance arms 3 provided in a female housing 1 and a pair of contact ribs 5 provided in a male housing 4. The resistance arms 3 and the contact ribs 5 are brought into contact with each other during the connection of the two housings 1, 4, thereby generating a large connection resistance. When the housings 1, 4 are pushed in connection directions with a force equal to or larger than a specified value, the resistance arms 3 and the contact ribs 5 suddenly are disengaged from each other, and the housings 1, 4 reach their connection completion position by inertial force and are locked into each other by a lock arm 2. Further, a waterproof ring 8 is mounted in the female housing 1. A pair of annular projections 6 formed on the outer circumferential surface of the waterproof ring 8 are to be pushed and deformed by a receptacle 7 of the male housing 4.
FIG. 10 shows changes in connection resistance values of the respective elements as the housings 1, 4 of the watertight connector are connected. Here, the connection resistance value of the watertight ring 8 is confirmed to change in such a manner that peaks P1 (see FIG. 10) are reached when the leading end of the receptacle 7 move over the respective annular projections 6. In this watertight connector, the peaks P1 of the connection resistance value of the annular projections 6 are reached after a peak P2 of the connection resistance value of the inertial locking mechanism comprised of the resistance arms 3 and the contact ribs 5 is reached. Accordingly, a difference between the resistance value during the restriction of the connecting operation by the inertial locking mechanism and that after the cancellation of the restriction cannot be made clear and, therefore, the operator cannot sufficiently feel and notice that the connection has been completed.
Published European Application No. 0 803 937 discloses a watertight connector similar to the above one. This watertight connector has a waterproof ring having three annular projections formed thereon, but still has a problem similar to the above.
In view of the above problems, an object of the present invention is to provide a watertight connector with an inertial locking mechanism, housings of which can be connected while making an operator feel and notice the completion of a connecting operation.